(1) Field of the Invention
The present invention relates to an ink supplying apparatus adapted for a rotary press using different color inks having various viscosities. More particularly, the present invention relates to an ink supplying apparatus which can always supply a constant quantity of ink to the downstream roller in combination with the cells formed in a mesh roller.
(2) Description of the Prior Art
Conventionally, ink has been constantly supplied by using a mesh roller. In detail, ink is excessively applied to the mesh roller to fill the ink into the cells and then the excess ink out of the cells is removed from the mesh roller by using a doctor blade. The ink filled in the cells; constant quantity, is directly supplied to a printing roller or through some rollers to transfer the ink.
In order to excessively apply ink to the mesh roller, conventional systems as shown in FIG. 7 to FIG. 9 have been employed. In FIG. 7, a mesh roller 101 is rotated with immersing a part of the circumferential surface of the roller 101 in the ink stored in an ink fountain pan 102. The excess ink is removed from its surface by scraping function of a doctor blade 104 which contacts with the circumferential surface of the mesh roller 101. In FIG. 8, a fountain roller 103 is partially immersed in the ink in the ink fountain pan 102 and a gap l is defined between the mesh roller 101 and the fountain roller 103. The ink on the fountain roller 103 is supplied to the mesh roller 101 through the gap l. The ink is filled into the cells formed in the mesh roller 101 with the pressure caused by rotating motion. The excess ink is removed from its surface by scraping function of a doctor blade 104 which contacts with the external surface of the mesh roller 101. In FIG. 9, the mesh roller 101 is provided with an ink nozzle having a closed space 105 defined by doctor blades 104. Ink is applied from the ink nozzle to the surface of the mesh roller 101 under pressure to fill the ink into the cells. Then the excess ink is removed from the mesh roll 101 by scraping function of the doctor blade 104.
In these conventional systems, the contact angle of the doctor blade is fixed or moved within an angle of 2.degree. to 3.degree.. If such systems are employed in a rotary press for color printing, such fixed doctor blade may not perform its scraping function when the viscosity of the ink is relatively high or varied on its colors. This may cause fluctuation such as over-supply or under-supply of ink amount, thereby resulting in printing faults.